Authors: Hiroshi Maeda
Addresses: Fukuoka Institute of Technology, Wahiro-Higashi 3-30-1, Fukuoka 811-0295, Japan
Abstract: Propagation and filtering characteristics of two dimensional pillar-type photonic crystal waveguide with triangular lattice were measured by a scale model in microwave frequency with lattice period P = 26.5 mm, diameter of pillar φ = 7.5 mm and its dielectric constant εr = 36.0 around 4 GHz. First, symmetric Y-branch waveguide was set up by using line-defect in array of pillars. Two kinds of set of pillars which have length of 3.0P and 2.5P, were situated in each output waveguide as cavities to show and good resonances and extinction ratios. Next, cascaded Y-branch with four cavities with different lengths at each output port was observed, but unnecessary resonances appeared near main peaks of filtered frequency. To suppress them, stabs with length of λg/4 of unnecessary resonance were inserted after the cavities. Due to the stabs, peaks of the unnecessary resonances were suppressed over 20 dB. This structure is applicable as a filter component in wavelength division multiplexing (WDM) systems in photonic crystal optical or microwave circuits.
Keywords: microwave frequency; scale modelling; photonic crystal waveguide; Y-branch waveguide; cavities; stabs; wavelength division multiplexing; WDM; optical circuits; microwave circuits; unnecessary resonances; filter components.
International Journal of Space-Based and Situated Computing, 2013 Vol.3 No.4, pp.227 - 233
Received: 14 Aug 2013
Accepted: 18 Sep 2013
Published online: 23 Aug 2014 *